1. Field of the Invention:
The present invention relates to a helical scanning type magnetic reproducing device for reading out picture information on a magnetic tape by means of a rotary magnetic head, particularly capable of still picture reproduction.
2. Description of the Prior Art:
In a conventional helical scanning type magnetic reproducing device the recording or the reproducing operation is carried out while a certain determined back tension is imparted to the magnetic tape wound around the tape guide drum in which a rotary head is provided.
The manner whereby back tension is imparted to the tape is well known in the art and a detailed explanation will not be provided herein. The most generally applied method involves, for example, braking of the feeding reel with a certain determined force. Furthermore, during a reproduction operation it is necessary to impart to the tape the same tension as during a recording operation so as to prevent distortion and to guarantee a certain determined pressure of the head upon the tape. For example, during ordinary reproduction operation, it is sufficient to impart to the feeding reel stand the same braking force as during recording operation. However, during still picture reproduction the tape stops running so that it is difficult to provide in the tape a certain determined back tension by means of the mechanism for braking the feeding reel. Consequently at the time of still picture reproduction the tension in the tape is changed as compared with during the time of the ordinary reproduction, thereby causing distortion which will curve the upper part of the picture plane or change in the pressure of the head on the tape which will adversely influence the picture quality.